(a) Field of the Invention
The present invention relates to a method for preventing a loss of trip data in a vehicle cluster. More particularly, the present invention relates to a method that may prevent trip data of a cluster from being lost or initialized without an additional voltage stabilizer or an electrically erasable programmable read-only memory (EEPROM) for storage when an instantaneous low voltage state occurs in the cluster due to start-up of a vehicle or a large electric load.
(b) Description of the Related Art
Recently, most vehicles are equipped with a cluster mounted with a trip computer, which provides a driver with information on average fuel efficiency, instantaneous fuel efficiency, traveled distance, average speed, driving time, and distance to empty (DTE) via a display.
The trip computer may indicate: the average fuel efficiency by calculating fuel consumption over a certain traveled distance, the current fuel efficiency by calculating the fuel consumption over the traveled distance for a certain time, the total traveled distance by adding the traveled distances of a vehicle, the average speed from the start driving point to the current driving point, and the DTE by calculating a drivable distance using the amount of remaining fuel and the fuel efficiency set for the corresponding vehicle.
In particular, as shown in FIG. 1, the trip computer may include a processor (Micom) 20 for calculating data such as average fuel efficiency and traveled distance which may be presented on displays using various kinds of intra-vehicle signals, for example, all signals inputted from a signal input unit 11 such as engine control unit (ECU), transmission control unit (TCU), automatic brake system (ABS), and a vehicle speed sensor. When a driver manipulates a reset button 13, the Micom 20 may delete data stored in a memory and may reset the display information such as the average fuel efficiency and the traveled distance.
Also, the trip computer further includes a memory 30 for storing data calculated by the Micom 20, a display 40 for displaying various kinds of information including the average fuel efficiency and the traveled distance calculated by the Micom 20, a mode switching button 12 for switching the display modes of the trip computer by a driver, and a reset button 13 for resetting the data value of each display mode to zero by a driver.
The memory 30 may include a Random Access Memory (RAM) 31 in which data processed by the Micom 20 may be stored. When the power supply to the RAM 31 is cut off, all data stored in the RAM 31 may be lost. Furthermore, when a user manipulates the reset button 13, all data stored by the Micom 20 may be deleted and reset in communication therewith.
The memory 30 of the trip computer further includes an EEPROM 32 for permanently storing data. Data stored in the EEPROM 32 may be maintained regardless of power supply to the trip computer and the cluster. The cluster includes a set of instrumentations displayed on the trip computer, such as the fuel efficiency, traveled distance, average speed, driving time and distance to empty.
On the other hand, when a voltage lower than 5V instantaneously occurs due to a battery voltage drop (occurrence of battery reset after start-up) under a start-up condition of a vehicle or a large electric load condition, the cluster is reset. In this case, unlike a periodic normal operation loop of the trip computer, all data stored in the RAM 31 of the trip computer may be deleted (cleared), and simultaneously, all display data may be reset.
The stored data is not deleted when a driver normally performs the reset manipulation, i.e., when the driver intentionally manipulates the reset button 13. Instead, the data may be deleted when data of the trip computer are unexpectedly lost and forcibly reset. Accordingly, a user may misperceive the reset of data as an abnormal operation.
With the recent development of technology, the start-up condition of the vehicle may be possible at a battery voltage lower than 5 V, which is a level of voltage lower than the minimum operation condition for reliability functions such as intra-vehicle communication or the normal operation power voltage for electric components.
On the other hand, in a conventional trip computer, the Micom 20 needs a voltage of 5 V or more supplied via the regulator for stable operation. However, when the trip computer is maintained at a voltage less than 5 V for a certain time, the Micom 20 may be reset, and all data stored in the RAM 31 may be deleted and reset (for example, forcible switching to trip computer mode, average fuel efficiency displayed as ‘_._’, traveled distance displayed as ‘0 km’, average speed displayed as ‘0 km/h’, and driving time displayed as ‘00:00’).
To prevent the unexpected reset of the trip data (data of the trip computer in a cluster), i.e., the occurrence of the reset of the trip data due to the voltage drop, a separate voltage stabilizer (application of a dual regulator circuit) may be added, or a method of continuously storing all trip data generated in real-time by the Micom 20 in the EEPROM 32, a nonvolatile memory, may be applied. However, these alternatives may cause an increase in the manufacturing cost due to the addition of the circuit or the use of a large capacity of EEPROM.
The above information is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.